A study just released this week in Science indicates the Pacific Ocean may be warming at a rate faster than it has in the last 10,0000 years [pay wall]:

Observed increases in ocean heat content (OHC) and temperature are robust indicators of global warming during the past several decades. We used high-resolution proxy records from sediment cores to extend these observations in the Pacific 10,000 years beyond the instrumental record. We show that water masses linked to North Pacific and Antarctic intermediate waters were warmer by 2.1 ± 0.4°C and 1.5 ± 0.4°C, respectively, during the middle Holocene Thermal Maximum than over the past century. Both water masses were ~0.9°C warmer during the Medieval Warm period than during the Little Ice Age and ~0.65° warmer than in recent decades. Although documented changes in global surface temperatures during the Holocene and Common era are relatively small, the concomitant changes in OHC are large.

This study was also reported in the LA Times, where some (genuine) climate scientists expressed scepticism about the rate of warming. Still it is very clear the oceans have been acting as a “buffer” in absorbing additional heat. However we can’t bank on the oceans performing this role in future centuries.